Posted
by
Soulskill
on Wednesday June 18, 2014 @01:08AM
from the get-off-my-lawn dept.

angry tapir writes: Unisys is phasing out its decades-old mainframe processor. The chip is used in some of Unisys' ClearPath flagship mainframes, but the company is moving to Intel's x86 chips in Libra and Dorado servers in the ClearPath line. The aging CMOS chip will be "sunsetted" in Libra servers by the end of August and in the Dorado line by the end of 2015. Dorado 880E and 890E mainframes will use the CMOS chip until the servers are phased out, which is set to happen by the end of 2015.

I first became aware of Unisys in the '80s when the Australian TV broadcasters used their stuff for instant replay, drawing annotations over stills, and slow motion. They got to display their "Unisys Computer" logo in the corner. Never actually had to use them professionally though. Looks like the future is becoming homogenous. IBM dropped the specialised AS/400 and System Z CPUs and migrated to POWER; everyone else seems to be dropping specialised CPUs and moving to x86 or POWER as well.

So they are looking for Rosetta - the technology Apple acquired for running PPC binaries on the x86 using binary translation.

Well, good luck to them; even though they could just license the technology, they probably won't. The job posting says they are relying on LLVM-IR as a means of translating the code.

In case they care, Apple acquired the company that produced Rosetta, so that's where you want to start to license it, or Facebook last year acquired a small company that did the same type of thing. I doubt they'd be able to hire the engineers away from Google, but if they're interested, Google has NACL and PiNACL which have to use similar techniques.

...and there's a good reason that Avie Tevanian went with "fat binaries" instead of TenDRA style ANDF or IR, and there's a good reason we (at Apple) extended it to Intel systems, rather than continuing on with Rosetta (though, to be fair, there isn't really a technical reason for the death of Classic or Rosetta, other than a broken build and archival process, really).

I don't know much (ok, anything at all) about the Libre lines but the Dorado machines have some very unusual characteristics such as 9-bit bytes which would render anything other than hardware compatibility a total disaster necessitating a forced conversion to another platform immediately.

Right. Goes back to the multiple-of-9-bit native word length of the the entire 11xx/22xx heritage, back to the Univac 418 [wikipedia.org]. Since bytes aren't the native access mode in that architecture anyway, they're an afterthought and rather harder to code for in assembler.

That's not the only oddity of that architecture, too. 1s complement math? Negative zero?

Yeah. I'm an old grey geek that started out on an 1180 back in the day. Mostly assembler real-time stuff.

I'm a bit misty-eyed at the thought of that heritage code running, essentially, by run-time emulation rather than natively.